ESTIMATION OF EFFECTIVE SHEAR STRESS WORKING ON FLAT SHEET MEMBRANE USING FLUIDIZED MEDIA IN MBRs

• Zaw Hlwan Moe

  東京都市大学大学院 工学研究科都市基盤工学専攻

• LI Tairi

  東京都市大学大学院 工学研究科都市基盤工学専攻

• NAGAOKA Hiroshi

  東京都市大学 工学部都市工学科

• MISHIMA Iori

  埼玉県環境科学国際センター 水環境グループ

Bibliographic Information

Other Title

• 平膜状浸漬型MBRにおける担体投入による膜面有効せん断応力の評価

Abstract

 This study was aimed at estimating effective shear stress working on flat sheet membrane by the addition of fluidized media in MBRs. In both of laboratory-scale aeration tanks with and without fluidized media, shear stress variations on membrane surface and water phase velocity variations were measured and MBR operation was conducted. For the evaluation of the effective shear stress working on membrane surface to mitigate membrane surface, simulation of trans-membrane pressure increase was conducted. It was shown that the time-averaged absolute value of shear stress was smaller in the reactor with fluidized media than without fluidized media. However, due to strong turbulence in the reactor with fluidized media caused by interaction between water-phase and media and also due to the direct interaction between membrane surface and fluidized media, standard deviation of shear stress on membrane surface was larger in the reactor with fluidized media than without media. Histograms of shear stress variation data were fitted well to normal distribution curves and mean plus three times of standard deviation was defined to be a maximum shear stress value. By applying the defined maximum shear stress to a membrane fouling model, trans-membrane pressure curve in the MBR experiment was simulated well by the fouling model indicting that the maximum shear stress, not time-averaged shear stress, can be regarded as an effective shear stress to prevent membrane fouling in submerged flat-sheet MBRs.

Journal

• Journal of Japan Society of Civil Engineers, Ser. G (Environmental Research)

  Journal of Japan Society of Civil Engineers, Ser. G (Environmental Research) 67 (4), 170-177, 2011

  Japan Society of Civil Engineers

Keywords

• submerged membrane bioreactor
• flat-sheet membrane
• effective shear stress
• fluidized media
• suction pressure

Details

• CRID: 1390001205356335488
• NII Article ID: 130004962373
• DOI: 10.2208/jscejer.67.170
• ISSN: 21856648
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed